Evidence from neuroimaging studies suggests that chronic cocaine use leads to white matter (WM) injury in frontal brain regions. Cocaine-induced damage to cortical WM can result in cognitive and behavioral deficits that may impact recovery and ongoing abstinence. There has been little in vivo study of the duration of cocaine's effect on WM microstructure, following abstinence; nor has the relationship between WM microstructure and cognitive function in active cocaine dependence (CD) or during recovery been addressed. Whether cocaine-induced changes in brain structure and function can partly or fully recover following the cessation of drug use has significant implications for the ongoing medical management of patients with CD, including their psychiatric treatment. Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) technique that can be applied to the study of WM integrity in vivo. DTI can be used to assess WM integrity by quantifying the magnitude and direction of tissue water mobility. Because water diffusion in WM is anisotropic (i.e., it is greater along the longitudinal extent of a nerve fiber when compared to diffusion along the short axis), this anisotropy can be quantified and used to assess the microstructural organization of WM using scalar measures such as fractional anisotropy (FA). Recent data have demonstrated decreased FA in the frontal WM in patients with active CD. This proposal intends to use DTI to study the persistence of cocaine's effect on WM integrity following cessation of cocaine use. We propose a cross-sectional design to study patients with a history of CD using MRI and neurocognitive assessments. Subjects will be recruited from a therapeutic community (Daytop) and compared with a group of healthy control subjects. Using DTI offers a significant opportunity to begin elucidating the relationship between WM integrity and recovery of neuropsychological function following cocaine abstinence. These data will help assess the feasibility of a longitudinal study of WM changes related to CD and potentially inform future treatment options.